The 3rd Generation Partnership Project (3GPP) launches an evolved packet system (EPS) on the basis of the existing 2nd generation (2G) mobile communications, and 3rd generation (3G) mobile communications. An EPS network includes an evolved universal mobile telecommunication system territorial radio access network (E-UTRAN) and an evolved packet core network (EPC). In an early stage of network construction of an EPS network, an operator already has a mature circuit switched (CS) network. However, the EPS network processes only a packet switched (PS) service. For protection of a CS network investment and a deployment policy of the EPS network, the operator may use an original CS network device to provide a CS service. Based on this requirement, the 3GPP extends a function of a Gs interface between a mobile switching center/visitor location register (MSC/VLR) and a serving GPRS support node (SGSN) in an existing 2G or 3G network, and defines an SGs interface between an MSC/VLR and a mobility management entity (MME) in an EPC network. Based on a function of the SGs interface, the 3GPP proposes a “circuit switched fallback” (CSFB) technology and a short message over SGs (SMS over SGs) technology. The CSFB technology enables a user equipment (UE) covered by an E-UTRAN, when a CS voice service needs to be processed, to fall back to a CS domain in a 2G/3G network through the E-UTRAN, so as to complete processing of the CS voice service. The SMS over SGs technology enables a UE residing in the E-UTRAN to reuse an existing CS domain device to implement transmission of a short message in the CS domain.
To greatly reduce a heavy cost for radio access network deployment by the operator, the 3GPP proposes a network sharing idea, that is, public land mobile networks (PLMN) of multiple operators, or multiple PLMNs of one operator may share a same radio access network to provide a wireless communications service. For the CSFB technology and the SMS over SGs technology, the operator also proposes a requirement for CS domain network sharing, and there are mainly the following two scenarios:
Scenario 1: A traditional operator upgrades an existing CS domain network (including a 2G network and a 3G network), so as to support the CSFB technology and the SMS over SGs technology, that is, the operator may provide, by sharing multiple PLMNs run by the operator or by sharing a PLMN of another operator by signing a roaming protocol, a CS service for a UE residing in an E-UTRAN.
Scenario 2: An emerging pure-PS service operator leases a CS domain network from a traditional operator by signing an agreement, so as to support the CSFB technology and the SMS over SGs technology.
In the foregoing CS domain network sharing scenario, for a same UE residing in the E-UTRAN, multiple available PLMNs may provide a CS service for the UE. In a combined attach procedure or a combined tracking area update procedure initiated by a UE, if multiple available PLMNs provide a CS service for the UE, an MME selects a proper PLMN according to a PLMN reported by an evolved base station (e.g, evolved node B, eNB), location information of a tracking area in which the UE is currently located, and a CS domain network selection policy of the operator. Based on the selected PLMN and the location information of the tracking area in which the UE is currently located, a corresponding CS domain location area identity (LAI) is assigned to the UE, and an associated MSC/VLR is selected based on the LAI. After the combined attach procedure is completed, the UE receives an attach accept message sent by the MME, where the attach accept carries a tracking area identity list (TAI list), the LAI, and a VLR temporary mobile subscriber identity (TMSI). For the UE, that the UE acquires the LAI and the VLR TMSI indicates that attach to the CS domain succeeds.
After the combined attach procedure is completed, the UE succeeds in registering with a network of the operator, and the UE should display a registered network name. Alternatively, after the combined tracking area update procedure, the UE should display the registered network name. Currently, the UE displays the network name mainly based on two policies.
Policy 1: Configuration is not performed on a network side, and the UE displays a network name according to a configuration of the UE.
Specifically, the UE displays, according to a PLMN identifier (ID) of a currently registered network, a network name corresponding to the PLMN ID.
However, in some scenarios, the UE cannot determine that a network name corresponding to which PLMN ID is to be displayed.
Policy 2: A network side delivers a to-be-displayed network name to the UE.
When receiving the network name delivered by the network side, the UE may use the received network name to update a network name configured on the UE, and display an updated network name.
(1) The MME notifies the UE of the to-be-displayed network name by using an E-UTRAN mobility management information (EMM information) message, and the UE displays the notified network name. The network name notified by the MME is determined by the MME according to a home PLMN (HPLMN) of the MME.
(2) The MSC/VLR delivers a network name of a registered CS domain network to the MME over an SGs interface. The MME notifies the to-be-displayed network name to the UE by using an EMM Information message, and the UE displays the notified network name. The network name notified by the MME is a network name of an HPLMN of the MME, where the network name of the HPLMN of the MME is determined by the MME according to a policy of the MME; or is a network name of a CS domain network registered through the MSC/VLR.
However, in a policy in which the network side delivers a network name to the UE for display, in some scenarios, the UE cannot determine a to-be-displayed network name, and the MME cannot know which network name the UE displays in fact either.